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Answer 1

+1 A:

Well, there seems to be some controversy about the CRUDy pattern and it's pros and cons. At a minimum, I would call a service interface that makes you write this kind of code to use it an anti-pattern (as commented here):

service.CreateCustomer(c);

foreach(Group group in c.Groups)

  service.AddCustomerToGroup(c.CustomerId, group.GroupId);

foreach(Person person in c.Contacts)

  service.AddCustomerContact(c.CustomerId, person);

Is exposing CRUDy interfaces bad in itself? I wouldn't say so. What's important is to provide an interface which will

encapsulate knowledge about the underlying processes
not be very chatty

Tomislav Nakic-Alfirevic 2010-03-16 08:40:12

The problem with the CRUD interface is that it will generally result in breaking the 2nd rule because multiple calls have to be made to do anything remotely complex - it will be "chatty".

Joe R 2010-03-16 08:48:19

Joe, do you have an example in mind?

Tomislav Nakic-Alfirevic 2010-03-16 08:59:36

The danger of a CRUD interface is that it encourages multiple calls. For example, for processing an Order there could be both an InsertOrder and InsertOrderLine method - two interface calls. This is in contrast to using one well-defined interface method to process the whole transaction.

Joe R 2010-03-16 09:14:12

I imagine those two methods would share logic. What kind of interface would you expose to support the "place an order" use case?

Tomislav Nakic-Alfirevic 2010-03-16 09:28:14

For a start I would have just one method that processes an order, the "four tenets of service orientation" in the paper I reference are a good check-list.

Joe R 2010-03-16 09:36:47

Hmmm...I think the vagueness of term "CRUDy" is what makes it a controversial subject. I (maybe mistakenly) thought about insertOrder() as a CRUDy concept even though if I were to implement it, it would handle order line insertion as well, along with everything else that happens when a new order is placed. In any case, I've bookmarked the paper you linked to for more detailed reading. :)

Tomislav Nakic-Alfirevic 2010-03-16 11:14:17

Answer 2

+1 A:

It does seem like the CRUD interface anti-pattern, but it would be good to see some interface examples to confirm.

This paper has a really good discussion on designing better service interfaces.

It includes a critique on, and alternative to, the CRUD anti-pattern.

Joe R 2010-03-16 08:41:47

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